Chapter 18-19 Air Pollution - PowerPoint Presentation

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Chapter 18-19

Air Pollution

There is no place on Earth that isn’t affected by air pollution…

Air pollution

: presence of chemicals in the atmosphere in concentrations high enough to harm organisms, ecosystems, human-made materials or to alter climateRanges from annoying to lethal

Refers to pollution in the troposphereNatural sourcesDust, wildfires, volcanic eruptionsHuman sources

Industrialized and urban areas

fossil fuel burning

Primary Pollutants: chemicals or substances emitted directly into the air from natural sources and human activities

Carbon monoxide, carbon dioxide, sulfur dioxide and nitric oxides; particulate matter; VOCs (natural sources—terpenes, plant fragrance)Secondary Pollutants: primary pollutants react with one another and natural components to form harmful chemicals, often in the presence of sunlight and water

Ozone, acid deposition (sulfates and nitrates) To determine and monitor Air Quality, the EPA actively monitors…carbon monoxideozone

lead

nitrogen dioxide

particulate matter (also known as particle pollution)

sulfur dioxide

Major Air Pollutants

Carbon OxidesCarbon Dioxide: from fossil fuel burning (major pollutant); is a greenhouse gas that impacts climate; required for photosynthesis; colorless and odorlessCarbon Monoxide

: from combustion of carbon (exhaust, forest burning, fossil fuels, tobacco smoke); Limits oxygen binding in hemoglobin which can result in heart attack, asthma, emphysema, nausea and death; colorless and odorless—dangerous indoor air pollutant

Nitrogen Oxides (NOx

) and Nitric AcidNitric Oxide (NO): combustion in cars, coal burning, lightning, part of soil and water (nitrogen cycle); colorless and odorlessNitrogen Dioxide (NO

2): nitrogen monoxide reacts with oxygen (NO2); reacts with water to form nitric acid and nitrate salts (acid deposition); forms photochemical smog (with sunlight); helps in the formation of

tropospheric

ozone; stinky, reddish-brown gas

Nitrous Oxide (N

2

O)

: greenhouse gas from fertilizers and animal wastes, also fossil fuel burning

** all are irritants to eyes, nose and throat, aggravate asthma and bronchitis; suppress plant growth and harm aquatic life

Sulfur Dioxide and Sulfuric AcidSulfur Dioxide (SO

2): 1/3 comes from natural sources (sulfur cycle), the rest is anthropogenic (coal burning, oil refining, smelting); corrosive gasSulfuric Acid: forms when SO2

reacts with water in the atmosphere, then falls as acid deposition (acid rain).**Aggravate breathing problems (respiratory irritant), decrease plant growth, corrosive

Particulates

Suspended particulate matter (solid particles and liquid droplets); particles smaller than 10 micrometers are regulated by the EPA as air pollution (not filtered by nose/throat)Outdoor: dust, wildfires, sea salt, coal/oil burning, cars (especially diesel), construction; road dust, rock crushing; volcanic activityIndoor: cigarettes, burning inside (developing countries)

**Aggravate eyes, nose, and throat, damage lungs, asthma/bronchitis, genetic mutations, and cancer (premature death)**Reduces the amount of incoming solar radiation (weather)

Ozone (O

3)Secondary pollutant that contributes to photochemical smogTropospheric ozone bad. Stratospheric ozone good.Ozone thinning is the stratosphere…which increases the amount of UV radiation that reaches us

Damages living tissueResults from release of CFCs and other Freons…from coolants and aerosolsMontreal Protocol—Limit these chemicals in manufactured products

**Coughing and breathing problems (asthma and emphysema), lung/heart disease, irritant; damaging to rubber and plastic

Volatile Organic Compounds (VOCs)Organic compounds (hydrocarbons) that exist as gases in the atmosphere

Give off strong aroma (paint, perfume, gasoline, flatulence)Help in formation of smog, not all hazardous…but some have the potential to be harmful

Ex. Methane—greenhouse gas from landfills, cows, decomposition, oil and gas burning/refiningOthers include benzene, industrial solvents, gas and plastics

Mercury: found in coal and oil, released from fossil fuel burning, can settle out into water. Seeing bioaccumulation into food chains.

Toxin for central nervous systemLead: occurs naturally in rocks and soils, also present in fuels and paints.Toxic to central nervous system (children), affects learning, concentration, and intelligence

Factors Affecting Air Pollution

Increase air pollutionBuildings break up windHills/mountains decrease air flowHigh temperature increases reactions

Emissions of VOCs increase smog formationTemperature inversions (warm air over cool)Decrease air pollutionHeavy particles settle out of airRain/snow cleanse air

Salty sea spray washes air

Winds mix air

Pollutants removed by reactions

Acid Deposition

Air pollutants mix with water in air to form acidic precipitation (acid rain)Nitrogen and sulfur oxides—form nitric and sulfuric acid (pH ~5)Has been occurring since the Industrial RevolutionUsually a regional problem…downwind of coal burning facilities

Pollutants are moved by windsDamages statues, buildings; causes respiratory diseases, leach toxic metals into the environment from rocks; harmful to aquatic ecosystems, hurts agriculture, and weakens forests and plantsReduced by limiting emissions of pollutants (alternative energy sources)

Smog

IndustrialUnhealthy mix of sulfur dioxide and sulfuric acid and solid particlesComes from coal burning in large quantitiesRarely a problem in developed countries…big problem in developing (China)

Sulfur dioxide and sulfates mostly; “grey smog”PhotochemicalMixture of primary and secondary pollutants formed under the influence of UV radiation“brown smog”—made up mostly of ozone

Indoor vs. Outdoor Air Pollution

Indoor Air Pollution from burning wood, charcoal in open fires or poorly designed stoves; cigarette smokeCarbon monoxide and particulatesImpacts high poverty/poor countries

Sources include:Tobacco smoke formaldehydeRadon gasFine particulatesPesticide residues

Lead

Organic solvents

Living organisms (mites, roaches)

Mold and fungal spores

Radon Gas

Colorless, odorless radioactive gas that is produced by the radioactive decay of uranium-238 (from underground rock)Only problematic in certain areas of the countryCan seep through cracks in the foundation and build up to harmful levels in air, or seep into groundwater

Damages lung tissue and lead to cancer (second leading cause of lung cancer)Radon-222 decays to Polonium-210 (harmful/carcinogen)

Dealing with Air Pollution

Clean Air Act: set aside air pollution regulationsEPA monitors pollutants and sets standards for emissionsEPA's mission is to protect human health and the environment. To achieve this mission, EPA implements a variety of programs under the Clean Air Act that focus on:

reducing outdoor, or ambient, concentrations of air pollutants that cause smog, haze, acid rain, and other problems;reducing emissions of toxic air pollutants that are known to, or are suspected of, causing cancer or other serious health effects; andphasing out production and use of chemicals that destroy stratospheric ozone.

These pollutants come from stationary sources (like chemical plants, gas stations, and

powerplants

) and mobile sources (like cars, trucks, and planes).

Buy and sell pollution allotments

Prevention in best solution!

Improve fuel efficiency standards

Alternative energy sources

Educate public about pollution

Air Quality Index

National Ambient Air Quality StandardsEPA sets standards for pollutants harmful to humans or the environment (clean air act)

Primary standards protect public healthSecondary standards protect public welfareCarbon Monoxide, Lead, Particulates, Ozone, Nitrogen Dioxide and Sulfur Dioxide